The Monster Raving Loony Party was not impressed.

Derrill Carr, a Campaign for Real Ale member who has helped the party launch its ales, told BuzzFeed News: "We're absolutely furious. They've pinched our idea.

"The ALE in Co-ALE-Ition clearly stands for Another Loony Experience. David Cameron definitely knew about our pump clip because it's in the House of Commons bar and his local pub in Witney.

"They didn't need to produce another ale, they could have just used one of ours. We've got 10 to choose from. They've pinched our brand and they've used it for their own publicity."

But Chris Keating from Wychwood Brewery said: "We're delighted the prime minister has chosen to support a local business from his constituency to reflect on the last five years and commemorate the occasion with a specially crafted beer for his colleagues."

Emily Ashton is a senior political correspondent for BuzzFeed News and is based in London.